Task switch is an efficient experiment to evaluate human's cognitive flexibility in which task cuing can effectively measure the cognitive process of task switching. In order to deeply study the cognitive process

we design the task cuing where the ratio of cue and target is 1:8. The neural oscillation of task switching was studied by combining event related potentials (ERP) and time-frequency analysis including event-related spectral perturbation (ERSP)

inter-trial phase coherence (ITPC)

event-related phase cross coherence (ERPCOH) in this paper. For P200

the experiment result shows that the neural oscillation has phase synchronization between prefrontal cortex and posterior partial cortex and the phase angle of posterior partial cortex lags behind prefrontal cortex

indicating that the brain completed task rule retrieval and P200 reflects a top-down process driven by prefrontal cortex. For P300

the research results of theta band oscillation distribution show that the brain activation in the cue switch was significantly greater than in the cue repeat. Meanwhile

the power of theta band oscillation was mainly distributed in the posterior partial cortex

which shows that theta band oscillation is related with the reconfiguration and update of task set. The above findings provide a new way to reveal the neural oscillation mechanism of brain cognitive flexibility

which helps us to understand the cognitive process of task switching.